Self-cleaning digging wheel buckets



May 13, 1958 F. F. KOLBE 2,834,128

SELF-CLEANING DIGGING WHEEL BUCKETS Original Filed Oct. 1, 1952 INVENTOR.

EM X1344, 19M

Unite States SELF-CLEANING DIGGING WHEEL BUCKETS Frank F. Kolbe,Winnetka, 11L, assignor to The United Electric Coal Companies, Chicago,111., a corporation of Delaware Original application October 1, 1952,Serial No. 312,517. and this application May 23, 1956, Serial No.

4 Claims. (Cl. 37-189) The present invention relates to wheel excavatorsof the bucket wheel type and, particularly, to improved buckets fordigging wheels. The present application is a division of my copendingapplication, Serial No. 312,517, filed October 1, 1952, now abandoned,and relates to improvements in self-cleaning buckets of the characterdisclosed in my copending application, Serial No. 585,335, filed May 16,1956, a continuation-in-part of my said application, Serial No. 312,517.

In the utilization of conventional digging wheels, the

structure of which is well known, the wheel is rotated to force thebuckets at the periphery thereof into the earth to scoop up earthmaterials. The material is carried upwardly by the buckets and, atapproximately the top point of bucket rotation, the material is supposedto gravitate out of the buckets and onto a suitable conveyor or the likefor removal and disposal. However, when excavating earth materials suchas mud, clay and the like, the material tends to stick to and in thebuckets even at the top point of bucket rotation so that upon subsequentengagement of the buckets with the earth, little or no excavation canoccur. With other types of earth materials, there is a gradual butconsistent and fairly rapid build-up of earth materials on the surfaceof the buckets which eventually renders the buckets useless. In eithercase, operation of the wheel must be stopped and the buckets must becleaned manually.

The primary object of the present invention is to provide improvedbuckets for digging wheels, which buckets are automaticallyself-cleaning so as to prevent retention of relatively sticky or gummyearth materials in the buckets and to prevent gradual build-up of earthma-.

terials in the buckets.

According to the present invention, 1 provide an improved bucket fordigging wheels having at least a portion of the rear or back wallthereof defined by a flexible and movable mat. By providing the mat inthe rear wall of the rigging wheel bucket with clearance at the sidesthereof, the creation of a suction or vacuum pressure condition in thebucket, which would prevent discharge of earth materials, issubstantially prevented. The mat is flexible and movable so that whenthe bucket reaches the top of its rotation, the mat moves inwardly toreduce suction, to force material out of the bucket and to break up anymaterials tending to adhere to the surfaces of the bucket in the path ofmat movement. Accordingly, it will be appreciated that buckets providedwith the aforesaid mat are rendered automatically self cleaning.

In addition to the foregoing, the mat accommodates the escape ofquantities of water and other fluids so that the bucket is adapted toexcavate a full measure of earth material. Also, the mat is responsiveto vibrations of the wheel so as to break up and discharge earthmaterials in the bucket and to prevent gradual build-up of materials onthe walls of the bucket.

It is the object of the present invention to provide an improved mat forself-cleaning buckets of the character ward edge or wide end thereof,the bucket is flared out- 2,334,128 Patented May 13, 1953 as i describedcomprising a sheet of rubber or the like pivotally attached to thebucket at its ends and with its sides being free for movement and forventing of liquids and suction conditions.

Stated more completely, the object of the invention is to provide animproved self-cleaning digging wheel bucket comprising a metallic buckethaving a large opening in the rear wall thereof and a flexible, movablemat closing the opening, the mat comprising a sheet of flexible materialmounted for movement with respect to the remainder of the bucket tofacilitate the discharge of earth materials.

Other objects and advantages of the present invention will becomeapparent in the following detailed description of a preferred embodimentof the invention, wherein reference is made to the accompanying drawing,in which:

Figure 1 is a side elevation of a digging wheel and its associatedapparatus; and

Figure 2 is a vertical sectional view, on an enlarged scale, of apreferred embodiment of a digging wheel bucket formed according to thepresent invention. The dotted line position of mat 50 is intended toshow a discharge position of the mat when the excavating bucket is in anupside-down position from that of Fig. 2. The dot-dash outline of mat 5tshows one position of the mat following discharge and as the excavatingbucket is rotating to its lower, excavating position.

Referring now to Figure 1, the present invention is particularly adaptedto excavating apparatus comprising, generally, a digging wheel 10rotatably supported at the free end of a digging ladder 12. The diggingwheel 113 is provided with a plurality of buckets 14 at its periphery.Each of the buckets is provided at its forward edge with teeth 15adapted to cut into a bank of material to be excavated by the excavatingapparatus and is otherwise formed as described hereinafter. Inoperation, the digging wheel is rotated in the direction indicated bythe arrow in Figure 2 to effect an upward cutting action against a bankof material. The teeth and leading edge of the bucket 14 cut into thematerial and force material into the bucket 14. As the buckets continueto rotate toward the top center of the wheel, the open bottoms thereofare closed by a stationary plug 16 adapted to retain the earth materialswithin the buckets until the buckets pass upwardly to a desired point.As the buckets pass the upper edge of the plug 16, the material thereingravitates onto a slope sheet 18 or like means which is adapted todirect the material onto a slope sheet roller 26) which transfers thematerial from the slope sheet 18 onto a conveyor 22. The conveyor 22conveniently leads to a point of disposal.

The digging wheel buckets 14, individually, that is as formed separatelyof the wheel, each conventionally comprise a metallic three-walledbucket, preferably a unitary casting, including a pair of side walls 24and a rear or back wall 26 joining the side walls. The side walls 24,

as viewed in elevation, are each generally beak-shaped, or are in theform of one-half of a crescent, and the rear wall 26 is arcuate toconform to the outer peripheral margins of. the side walls. The bucketsare mounted on the wheel with the narrow or generally pointed endthereof extending within the confines of the. wheel and the wide oropenend thereof extending radially beyond the periphery of the wheel.Each bucket is suitably secured to the wheel, preferably by weldingportions of the side walls to the rims of the wheel and by welding thenarrow or pointed endof the bucket to a rod 28 secured to and extendingtransversely of the wheel. At the forwardly to provide an entry opening,and the plurality of teeth are suitably attached to the leading orforward edge of the bucket to cutinto andbreakup the earth materials.

According to the present invention, conventional bucket design may beadhered to, but, as shown in Fig: ure' 2, an aperture or opening isprovidedthe rear wall 26* of the bucket, which opening is closed by amat 32. The mat 32 is flexible and is so mounted as to be capable ofmovement with respect to the rear wall of the bucket. The opening 30 maybe formed of any desired size, but preferably is ofa size correspondingat least to approximately 75% of the area of the rear wall. The openingis preferably spaced from the forward edge of the wheel so as not toweaken the leading edge and tooth supporting portion of the bucket.While I have shown the aperture or opening 30 as being provided only inthe back or rear wall of the bucket it will be appreciated as thedescription proceeds that the opening may extend into the side walls orthe bucket if desired. Accordingly, it willbe appreciated that thebucket of the present invention comprises a metallic bucket having aportion of atleast the back wall hereof defined by a flexible andmovable mat. V

The mat 32 may be formed of various flexible sheet. materials, and apreferred form thereof is disclosed in Figure 2 as comprising arectangular sheet 50 of rubber or rubber-like material. The sheet 50 maybe fabricated in any customary manner and may include fabric or metallicreinforcing members. In this respect, I dontemplate that fabricreenforced conveyor belting will be a practical material.

To secure the mat to the bucket within the opening 30, a plurality ofU-shaped brackets 38 are secured to the bucket at each end of theopening in spaced parallel relation with the bight portion of the Uspaced from the edge of the opening. The legs of each bracket engage theopposite surfaces of the bucket and are secured thereto, suitably bywelding. The bight portions of the U- shaped brackets comprise hingeleaves or the like adapted for the reception and support of a mountingpin, pintle pin, or rod 40 at each end of the opening 30. At theopposite ends thereof, the rubber sheet is suitably stepped or serratedto provide spaced hinge portions 52 adapted to extend between adjacentU-shaped brackets 38 for the passage of the pintle pin 40. Preferably,metallic sleeves 54 are positioned within, preferably by molding thesame in, the hinge portions 52 of the sheet 50 for reception andguidance of the pins 40. If desired, the pins 40' may suitably besecured to the respective brackets 33, as by welding. Further, the pinsor rods 40 may be positioned in alignment with, or in the same plane as,the back wall of the bucket to prevent disassociation of the pins. Also,if desired, the assembly of the mat, the brackets and the pins or rodsmay be made separately and then secured as a unit to the bucket. Thesheet material 50 is not connected to the bucket at the sides of theopening 30 so that the same will have freedom of movement in response toactuation of the wheel.

In use of the buckets, the mat at its free edges,'which are spaced fromthe bucket proper, will provide a vent to accommodate discharge offluids and to prevent the occurrence of a vacuum or suction condition inthe buckets. In addition, the sheet 50 will be capable of movement inresponse to gravity as the wheel is rotated and will also be subject towheel vibration to insure discharge of materials from the buckets and toprevent the accumulation of materials on the surfaces of the buckets.Since the mat area will remain clean, the surfaces of the side walls andthe forward portion of the back wall of each bucket will be renderedself-cleaning due to the fact that upon entry of the bucket into theearth any slight amount of material that may accumulate on such surfaceswill be forced intothe mat portion of the bucket. The buckets arereadily adapted for excavation of loose materials, such as sand andgravel, without the possibility of inefiicient excavating resulting fromloss of materials through the mat.

In view of the foregoing, it is to be appreciated that the mat, which isflexible in all directions and of a length greater than the shortestdistancebetween the front and rear edges of the opening in the back ofthe bucket, is freely movable into and out of the said opening and doesnot overlie or underlie any part of the bucket proper; Because of thesefacts, there is no portion of the that that will become rigidified orthat can in effect become bonded or confined against a surface of thebucket proper due to the repeated packing of earth, mud, clay and thelike into the bucket. Further, as the wheel is rotated, each mat ingravitating into the bucket falls rapidly downwardly to the substantialextent accommodated by its length (see Fig. 2) whereupon it is broughtup short and rebounds upwardly with a snap action resulting in flexingand shaking of the mat in all directions. to cleanthe same. Such. actioninsures that" the mats areautornatically self-cleaning. Furthermore, infalling or gravitating downwardly and in being flexed and shaken, theside edges of the mat perform a scraping action in relation to the sidewalls of the bucket, and this function, coupled with the self-cleaningfunction of the mat, renders each bucket automatically self-cleaning.

With respect to the structure of the digging wheel, it is to beappreciated that the buckets, particularly as having open backs, cannotprovide laterally thereof the degree of rigidity essential in excavatingwheels, and itisnecessary therefore to tie the two rims of the wheelto.-'- gether. To this end, I provide a reinforcing bar or red 42extending between the rims of the wheel 10, over the opening 30 andacross the back of each bucket more or less in abutting relationthereto. The primary purpose of the rods 42 is for wheel strength andrigidity,- but each also acts to prevent distention of the mat.- Therods 42 of course are not part of the bucket proper, and beingcylindrical, present such minute area to the mat as not in any way tointerfere With the automatic self-cleaning, functions of the mat aspreviously described,

From the foregoing, it will be appreciated that the present inventionprovides an improved digging wheel bucket for excavating apparatuswherein the bucket is: self-cleaning and insures eliicient use of theapparatus.v

While I have described what I regard to be a preferred embodiment of myinvention, it will be apparent thatvarious changes, rearrangements andmodifications may be made therein without departing from the: scope ofthe invention, as defined by the appended claims.

I claim:

1. In a digging wheel bucket having spaced generally parallel side wallsand an arcuate back wall joining theside walls, the back wall having anopening therein conn stituting the major portion of the back wall, theimprove-- ment comprising a sheet of flexible material mounted in saidopening, said sheet being of a width less than the width of said openingand of a length substantially greater than the shortest distance betweenthe front and rear edges of said opening, said sheet being hingedlyconnected solely at its forward and rearward edges to said: back walladjacent the front and rear edges of said opening, said sheet at theside edges thereof being freely spaced from and freely movable withrespect to the side edges of said opening, said sheet being freelyspaced from and not overlying or underlying the walls and surfaceportions of the bucket, said sheet being flexible in all directions andfreely movable into and out of said opening.

2 A self-cleaning digging bucket for rotatable excavab ing wheelscomprising a bucket including spaced generally parallel side walls andan arcnate back wall joining said ide walls and extending in a directioninwardly of'thej wheel from the lip to the tail end thereof, said backwall having a large generally rectangular opening therein constitutingthe major portion of the area of the back wall and leaving a relativelyshort back wall portion extending between said side walls at the lip endthereof, and a sheet of flexible rubber-like material disposed in saidopening and comprising substantially the remainder of the back wall ofthe bucket, said sheet being hingedly connected at its for- Ward andrearward edges only to said back wall in spaced relation to the forwardand rearward edges of said opening, said sheet being of a width lessthan the spacing between the side edges of the said opening, whereby theside edges of said sheet are freely spaced from and freely movable withrespect to the side edges of said opening, said sheet being freelyspaced from and not overlying or underlying the walls or surfaceportions of the bucket proper, said sheet being flexible in alldirections and of a length substantially greater than the shortestdistance between the front and rear edges of said opening, said sheetbeing freely movable into and out of said opening, said sheet when thebucket is disposed with its back wall down freely gravitating into saidopening and into the plane of said back wall substantially to conform tothe arcuate curvature of said back wall, said sheet when the bucket isdisposed with its back wall up freely gravitating a substantial distancedownwardly into the bucket toshake dirt, mud, clay and the like free ofthe bucket and said sheet and to effect a relative scraping action withrespect to said side walls to clean the same.

3. In a digging Wheel bucket having spaced generally parallel sidewalls, a lip portion joining said side walls at the lip end thereof anda tail portion joining said side walls at the tail end thereof in spacedrelation to said lip portion, saidsidewalls and lip and tail portionsdefining an opening, the improvement comprising a mat of flexiblematerial hingedly connected solely at its forward and rearward edges tosaid lip and tail portions respectively and constituting the greaterportion of the back wall of the bucket, said mat being of a widthsubstantially the width of said opening and of a length substantiallygreater than the straight-line distance between said lip and tailportions and being freely movable into and out of said opening.

4. A self-cleaning digging wheel bucket for excavating apparatuscomprising a bucket including spaced generally parallel side wallshaving an arcuate peripheral edge, a back wall portion joining theperipheral edges of said side walls at the lip end of the bucket, and aback wall portion joining the peripheral edges of said side walls at thetail end of the bucket in spaced relation to said back wall lip portion,said sidewalls and said lip and tail portions defining an opening, and asheet of flexible rubber-like material of a width less than the distancebetween said side walls and of a length greater than the shortestdistance between said back wall portions, said sheet being hingedlyconnected solely at its ends to the bucket in spaced rela tionrespectively to said back wall portions, said sheet at its side edgesbeing freely spaced from and freely movable relative to said side walls,said sheet being spaced from and not overlying or underlying any portionof the bucket and being freely movable into and out of said openmg.

References Cited in the file of this patent UNITED STATES PATENTS885,049 Holcomb Apr. 21, 1908

